[R129 SL] [R129 SL 500 Replace Blower Regulator

[Jan Kuylaars]

I FIXED MINE WITH SAME PROBLEM WITH TWO DROPS OF OIL AND A SATURDAY OF WORK:

In the past some times I discovered that the blower motor wont not operate
ore drove at low speed.Then turning on again the switch solved the problem.
Yesterday the motor did not operate at all. Turning several time the switch
did not change anything.
So I must repair the system. Because all the other functions on the half
automatic climate control were normal operating ,
I could hear the air-operated valves close  when I set the blower switch on
off and open when I used forced windshield heating on 6 ,
I now for 99% that the control box was not defective.
Looking on the ETM ( electronic trouble manual) on the MB USA DVD I could
see that there were four other parts that could be defect.
1-The Fuse F19 , placed near the big fuse box , above the brake vacuum box.
2-N29, the power control unit, placed on the blower motor.
3-The blower motor M2 , placed underneath the air inlet filter.
4- The wiring in this system, including the earth connection W1, placed
under the dashboard.
Off course I hoped that the last was not the issue.

So I started with taking away the rubber band that is positioned between the
air inlet and the motor compartment.
Then pulling the grey cap what is positioned between the windshield wiper
and the mechanic up from the wiper system.
Unscrew the bolt that holds the wiper arm on the system , and take of the
wiper arm by pulling it to the right.
Unscrew the left and right air inlet box by not taking out the screw, but
only loose them some turns. |For the inner screws near the wiper
Motor it is necessary to putt the screwdriver true the hole that is covered
by plastic taps. The hole looks like a cross.
After unscrew pull the outside ( mirror side ) up towards the roof for some
inches. The box becomes loose from the screws.
Then pull the right one to the right mirror side and the left to the left
mirror side. Because all the holes are on one side open,
you can now takeoff the boxes from the chassis.

Then unscrew the two bolts from the dust filter compartment , unclip the
three clips on the motor side and pull off the complete filter house cover.
Take out the sensor on the right side , careful take out the wiring and lay
the sensor on the motor air filter.
Unscrew all the Philips screws on the left computer compartment cover plate
and take off the cover plate.
Carefully take out the wire from the sensor that you lay down on the motor
air filter to the computer compartment.
The wire is positioned between the bottom from the airfilter compartment and
the chassis .
Pull out the green and yellow air pipes out off the connectors in the
computer compartment.
Pull out the round cover plate underneath the rubber from the wiper
mechanism.
Unscrew the left wiper motor cover plate  and the right air inlet cover
plate , they are fastened with two Philips screws and two plastic fasteners.
Take off these covers.

Now you can see the complete wiper system. Search for the wiper computer
positioned to the windshield side in the computer compartment.
On top of the computer there is a smaller relay box. on these relay box
there is the wiper motor connector. You can see it on the colours and the
thickness

>From the wires : on the right side it is green-white-black-yellow and brown.

The same like on the wiper motor. You also can follow the cable from the
wiper motor
To the relay box. Push the holder from the connector to the left so the
connector come off the relay box.

Now unscrew the two bolts which clamped this cable on the wiper motor.
Unsolder or un well the wires on the wiper motor. Started with the green
from the motor
And the cable, then the red from the motor and white from the cable, then
the black-yellow and brown. On the brown there is also an small brown wire
to the shell for earth
Pull the cable out off the compartment to the computer compartment. Be aware
not to damage the rubber seal so you can later putt it back perfectly
watertight.
Unscrew the under rubber holder from the wiper mechanism with a small 90
degrees wrench set.  Unscrew the rest from the mechanism with a 10 mm pipe
tool set.
Take out the wiper mechanism to pull it to wards the motor compartment.

Unscrew the left rubber mounting  from the wiper mechanism with a 22 mm
wrench set. Unscrew the other bolts with a 10 mm pipe tool out of the bottom
of the
Air filter compartment. Then use a 10 mm pipe tool that is at least 20cm
long and putt some chewing gum or other adhesive compound at the end.
That is that the bolts are not falling into the chassis but stay in the tool
to take them out of the car.
There are three bolts positioned in the bottom from the air filter
compartment between the iron chassis from the motor compartment and  the
plastic side wall

>From the air filter compartment. So you have only a half inch to do so. Also

the four other cables laying in this space can be a problem.
You can solve this problem by using a big flat screwdriver and pull one
cable to the air filter compartment, so you can use the pipe tool between
the cables.
( when you assemble you have no problem because then you have  the
possibility and space to lay all the cable's neat above each other to the
iron side  )
Now pull out the complete air filter bottom out of the car.

Now you can see the blower motor. Take off the green air pipe from the motor
. Take of the red and green wires from the motor.
Unclip the four clips on the right side from the vent cover, and two clips
from the left vent cover. Unclip the steel band what is holding the blower
motor on its place.
Now you can take of the motor complete with vents.

I tried to let the motor turn by hand, but it was very difficult. The
bearings were completely dried out. Checking the cowl browsers ; they were
OK.
Putting some oil on the bearings , and turning the motor by hand , loose the
bearings . Using an extern power supply from 12 volts 5 Amps let the motor
Turning faster and faster , and after some time and repeating the oil , the
motor turns like new.

So after assembling the complete system in reverse order like mentioned
above, I repaired my car with five drips of oil and four ours of  my own
labour.
Dissembling take 3 hours and assembling only one hour. That's because I then
new how to work. That's why I write it down for those people who must do the
same job.
At the same time I oiled the wiper system, let come out the arm by turning
the motor.


Friendly greetings from The Flying Dutchmen 500 SL



Jan Kuylaars Westerhoven

-----Oorspronkelijk bericht-----
Van: r129list-bounces at mbcoupes.com
[mailto:r129list-bounces at mbcoupes.com]Namens .
Verzonden: donderdag 19 april 2007 22:08
Aan: SL Mailing List
Onderwerp: Re: [R129 SL] [R129 SL 500 Replace Blower Regulator

Thanks for the blower regulator info.

Is this a procedure that a "weekend mechanic" can
do ?  Can you describe the procedure ?

Thanks in advance for your thoughts .

Bruce in Nashville - 1995 SL 500
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